Fig. 1.
Viability of human bone xenograft following implant into NOD SCID mice. Two 0.5-cm3 pieces of human femoral head were implanted subcutaneously into 8-week-old female NOD SCID mice (n = 5/group). Animals were culled and bone implants removed 0, 7, 14, 21 and 28 days following implantation for analysis of viability (a). Percentage of viable osteocytes was assessed following Giemsa staining (b). Uptake of fluorescently labelled calcein by viable cells 0 and 28 days following implantation of bone was detected by multiphoton microscopy (c). Structure of bone was assessed by uCT and bone integrity shown as % bone volume compared with total tissue volume (BV/TV%) (d). Effects on osteoclast and osteoblast numbers and origin are shown in (e). (i) X60 photomicrographs of osteoclasts and osteoblasts lining human bone 28 days after implantation. (ii) Numbers of osteoclasts and osteoblasts per mm of bone surface, and (iii) origin of these cells as identified by expression of mouse and human CTSK (osteoclasts) and RANKL (osteoblasts/osteocytes) normalised to GAPDH. All graphs show mean ± SEM from 5 mice per time point. Data represents mean ± SEM with statistical significance determined by one-way ANOVA. *p < 0.01, **p < 0.001, ***p < 0.001 compared with 0 h control